A conventional mechanism for opening and collapsing an umbrella generally includes a button which is located at the runner. The button has a spring strip which is hooked to the shaft to position the runner when the umbrella is opened. When the umbrella is to be folded, the user pushes the button and the spring strip is disengaged from the shaft so that the umbrella is folded. However, the button is located on the runner which might be rotated during use of the umbrella so that when the user wants to push the button, he or she has to rotate the umbrella to find out where the button is. Besides, the button might be touched unintentionally so that this is not convenient to the users.
Another conventional mechanism for opening and collapsing umbrellas known to applicant is shown in FIG. 9. When the umbrella is opened, the operation member 5 is pushed upward to push the protrusion 64 of the pressing portion 62 of the spring plate 6 inward by the contact surface 521 so that the locking end 63 of the spring plate 6 is engaged with the positioning hole 80 in the shaft 8. When the operation member 5 is moved toward the stop 71 of the runner 7, the contact surface 51 is removed from the protrusion 64 so that the locking end 63 is removed form the position hole 80 and the runner 7 then can be moved along the shaft 8 to collapse the umbrella.
The runner 7 has to be made larger so that the operation member 5 and the spring plate 6 are able to be cooperated with the runner 5. The larger runner increases the space that the collapsed umbrella occupies. Besides, fatigue will be a main concern for the spring plate 6 after frequent uses and once the spring plate 6 cannot be precisely positioned as desired, the umbrella is in an unstable status.
The present invention intends to provide a mechanism for opening and collapsing an umbrella wherein the user can simply pull or push an operation collar to achieve the opening or collapsing of the umbrella.